While society should be careful about its uses of genetic testing and its efforts to modify the genome, some people overreact when dealing with DNA. Consider two recent examples reported in the media.

A genetic cancer test. In a fascinating series on genetics in medicine, Gina Kolata reported in the New York Timeson a genetic test for ocular melanoma. The test distinguishes between curable and fatal forms of the melanoma, yet some physicians do not offer the test to their patients (though they disclose the availability of the test).

Of course, some patients may choose not to know which type of melanoma they have. Both curable and lethal types are treated in the same way--surgical removal--and knowing that death is certain may be too unsettling for a number of patients with the fatal form.

But to not even offer patients the chance to know seems odd. If the diagnostic test were not a genetic one, I suspect the physicians would act differently. For example, if doctors were able to distinguish between curable and fatal forms of ocular melanoma when tumor cells were sent to the pathology lab for standard cellular analysis, there would not be the same reluctance to offer patients the opportunity to find out which kind of tumor they had.

To be sure, the fact that a particular medical test is genetic may increase the potential for concerns with the test. But many genetic tests do not pose any special problems. Physicians should not let a genetic label mislead them.

Fighting dengue fever. A second example of problematic thinking about genetics appeared in the New Yorkerin an article by Michael Specter about genetic modification of the Aedes aegypti mosquito to eliminate dengue fever. If the mosquito can be eradicated, so can the dengue fever virus, which kills many and for which there is no vaccine or antiviral therapy.

When scientists proposed a trial of the genetically-modified mosquito in Key West, Florida, it encountered strong opposition. But many of the arguments that were invoked against a genetic strategy, rather than alternative mosquito-control strategies, did not make much sense. For example, opponents worried about the impact on plants and other animals from eliminating the Aedes aegypti mosquito even though scientists already are using pesticides to eradicate the mosquito and even though pesticides have toxic effects on plants and other animals. Or consider the fact that the mosquito is not native to the United States, so isn’t a part of the country’s natural ecology.

This is not to say we should be complacent with genetic modification. There can be real risks when a genetically-altered species is released in the wild. But genetic modification is not always harmful. Society should judge a genetic strategy fairly according to its actual benefits and risks.